metric drill set explained?

Topics include, Machine Tools & Tooling, Precision Measuring, Materials and their Properties, Electrical discussions related to machine tools, setups, fixtures and jigs and other general discussion related to amateur machining.

Moderators: Harold_V, websterz, GlennW

whateg0
Posts: 493
Joined: Sat Mar 28, 2009 3:54 pm
Location: Wichita, KS

Re: metric drill set explained?

Post by whateg0 » Tue Oct 02, 2018 9:23 pm

Russ, that's a good point about the half-nuts. On my 10ee, I have grown accustomed to leaving the half-nuts engaged anyway and using the ELSR. Makes threading to a shoulder almost boring, and I like it like that.

As far as standard thread pitches, I've been finding stuff with NEF more and more frequently, and looking through Machinery's Handbook to see if I got some oddball, there are a huge number of what we might call non-standard inch threads, too. Maybe it is a matter of them not being used as often as the oddball metric stuff.

WesHowe brings up another thing that I thought of this morning. For machinists and those of us who pretend to be machinists, the inch/metric comparison may be a bit skewed since as was pointed out, thousandths of an inch are still base-10.

For others who cannot find anything wrong with our customary measurement system, I don't know if I believe that, or if I think you just refuse to recognize the deficiencies. Much like languages, if you only know one language, then all others are probably inferior.

Dave

User avatar
NP317
Posts: 1445
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon

Re: metric drill set explained?

Post by NP317 » Tue Oct 02, 2018 9:59 pm

Just imagine calculating the speed of an African Sparrow!
... :lol:
~RN

Harold_V
Posts: 17142
Joined: Fri Dec 20, 2002 11:02 pm
Location: Onalaska, WA USA

Re: metric drill set explained?

Post by Harold_V » Wed Oct 03, 2018 2:01 am

GlennW wrote:
Tue Oct 02, 2018 12:50 pm
I haven't discovered the flaw in the Imperial system yet!
Yep, what Glenn said, although, by now, I think we recognize that here, in the US, while we measure by the inch, our system isn't really Imperial.

I've never suggested that the metric system isn't good---perhaps even better than what we use. However, do take note that major machine tool builders are still providing machine tools that work to the inch (as well as metric). Strange, considering I think that, aside from the US, there's only one other country using the same system. That should tell you something. For one---there's nothing wrong with the system--it works just fine. For another, they keep building machines for the system, because it's no secret that it is hugely popular amongst those of us who run (or ran, like me), machines for a living.

Can any of you imagine having to abandon everything you know and understand, as well as replacing all measuring instruments and machine tools, in order to use the metric system conveniently? No wonder the world hasn't been successful in forcing the conversion. Speaks volumes about the power of the US in the world economy, to say nothing of the prowess displayed in modern machinery and technology. Lets hear if for the inch! :P

H
Wise people talk because they have something to say. Fools talk because they have to say something.

User avatar
liveaboard
Posts: 535
Joined: Sun Dec 08, 2013 1:40 pm
Location: southern Portugal
Contact:

Re: metric drill set explained?

Post by liveaboard » Wed Oct 03, 2018 3:31 am

People sure do get excited by this subject.
Machine manufacturers will build whatever their customers want to buy; customers work in inches, machines are built in inches.
Here in Europe, machines are delivered metric, which means metric dials and slide screws. 'Metric' dosen't mean 'Chinese' here.
I was born in Inches and changed over. Personally, I like metric MUCH better than the archaic inch system I knew when I was young.

User avatar
tornitore45
Posts: 1568
Joined: Tue Apr 18, 2006 12:24 am
Location: USA Texas, Austin

Re: metric drill set explained?

Post by tornitore45 » Wed Oct 03, 2018 5:21 am

Bad Dog your experience with the availability of metric hardware is due to the fact that you live in the US and need metric. The same experience would apply to someone living in a metric country trying to procure Imperial hardware.
Should you live in a metric country you would have had no problem sourcing Kubota bolts in both coarse and fine pitch.
Mauro Gaetano
in Austin TX

User avatar
GlennW
Posts: 6654
Joined: Sun Apr 15, 2007 9:23 am
Location: Florida

Re: metric drill set explained?

Post by GlennW » Wed Oct 03, 2018 6:36 am

tornitore45 wrote:
Wed Oct 03, 2018 5:21 am
Bad Dog your experience with the availability of metric hardware is due to the fact that you live in the US and need metric. The same experience would apply to someone living in a metric country trying to procure Imperial hardware.
Should you live in a metric country you would have had no problem sourcing Kubota bolts in both coarse and fine pitch.
Exactly

It's purely the inconvenience of trying to work with the metric system that I despise, not the system.

As far as making parts goes, the parts are the same, it's just a different set of numbers applied to them.

The issue is that I have no metric metrology tools, no metric thread wires, I'm not familiar with metric thread standards or tolerances, and can't visualize size or distance in metric.

Everything results in a conversion back to US standards which is nothing more than a PITA and adds room for error...
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

User avatar
tornitore45
Posts: 1568
Joined: Tue Apr 18, 2006 12:24 am
Location: USA Texas, Austin

Re: metric drill set explained?

Post by tornitore45 » Wed Oct 03, 2018 7:33 am

I am equally at ease with both systems. I admit that for dimensions less that 10 mm my eye is calibrated in metric. My machines are imperial (except for the cross-slide screw that had a 1.25 mm lead long replaced with a 20 TPI - Chinese creativity)
Since my livelihood does not depend from my machining efficiency, nor the skills (thank God) I can spend the time to convert when making a metric part, no bid deal. Is an entirely different game if one in in business.
Mauro Gaetano
in Austin TX

earlgo
Posts: 1302
Joined: Sat Jan 29, 2011 11:38 am
Location: NE Ohio

Re: metric drill set explained?

Post by earlgo » Wed Oct 03, 2018 9:11 am

And then there are us poor US educated MEs that learned stress analysis in 'conventional' units and then got hired by a company that only used metric units. It was a struggle trying to deal with MPa or GPa instead of #/in^2 or N-m instead of Ft-# or °C instead of °F or kN instead of #, or remembering to multiply ft/sec^2 by 9.81 to get M/sec^2.
One poor student who shall remain nameless, did the inch to mm conversion backwards and screwed up an entire sheet metal design.
In addition the shop had a heck of a time finding metric hammers. :)
--earlgo
Before you do anything, you must do something else first. - Washington's principle.

User avatar
GlennW
Posts: 6654
Joined: Sun Apr 15, 2007 9:23 am
Location: Florida

Re: metric drill set explained?

Post by GlennW » Wed Oct 03, 2018 9:29 am

earlgo wrote:
Wed Oct 03, 2018 9:11 am
In addition the shop had a heck of a time finding metric hammers. :)
Did they ever find the tapered pipe taps?
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

User avatar
NP317
Posts: 1445
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon

Re: metric drill set explained?

Post by NP317 » Wed Oct 03, 2018 10:03 am

I was raised using the USA Standard measurement system. All OK with that.
However... I learned the Metric system recognizing it is the World Standard, and useful to my engineering success.
USA manufacturers use both systems, but increasingly metric, because they wish to sell outside our country's borders.

We raised our two sons in Seattle, in part so they would gain a more "world view", beneficial to their lives.
And we encouraged their use of Metric measurements, which has already shown useful results for their careers and general navigation outside of the USA.
As kids they used to choose to watch Canadian TV stations for weather reports because they used metric! I thought that was pretty funny, and useful.

My machine shop tooling is mostly inch-based, but all measurements systems are both inch standard/metric. I build stuff in both systems, as needed.
So goes modern life.
~RN

whateg0
Posts: 493
Joined: Sat Mar 28, 2009 3:54 pm
Location: Wichita, KS

Re: metric drill set explained?

Post by whateg0 » Wed Oct 03, 2018 11:08 am

Calipers in my shop are all inch/metric. Machines are all inch. DI are all inch, and 3 of my DTI are inch. When shopping for a DTI with better resolutions (read tenths), I ran across a BesTest 0.002mm for little money on Ebay. I have since watched several items like that go for far less than the inch equivalent just because they are metric. For use on a surface plate, it took some getting used to, but for use on the lathe, it was a no brainer. In terms of resolution, it's actually slightly better than a tenths DTI. Shortly after buying that DTI, I ran across another BesTest DTI, this time 0.01mm also for cheap. I have no problem using them.

Funny story from work... We build equipment that uses mostly #4-40 screws. Our sister company in the UK builds stuff using mostly 2 or 2.5mm screws. For a long while I had to listen to a lot of complaining from techs because the UK hardware kept ending up with stripped screws or holes. Damned metric stuff. Metric screws are junk! This is why inches are better! I think cheese is cheese, no matter the COO or standards.

Dave

User avatar
BadDog
Posts: 4546
Joined: Wed May 17, 2006 8:21 pm
Location: Phoenix, AZ

Re: metric drill set explained?

Post by BadDog » Wed Oct 03, 2018 11:43 am

tornitore45 wrote:
Wed Oct 03, 2018 5:21 am
Bad Dog your experience with the availability of metric hardware is due to the fact that you live in the US and need metric. The same experience would apply to someone living in a metric country trying to procure Imperial hardware.
Should you live in a metric country you would have had no problem sourcing Kubota bolts in both coarse and fine pitch.
Not really. My local fastener supply had both of the "standard" (most common) "fine" and "coarse" metric fasteners in the correct nominal diameters. The Kubota uses a pitch other than the most common on many of it's bolts. And it's not like firearms and metrology where they are trying for lock-in. The guy I talked to says they turn away a lot of metric business due to this same spread of supposed standards. His take based on what come through their doors was that metric manufacturers just pick a pitch from a full range without trying to stick to 2 per size. My add would be that it's probably based on whatever popped out of their engineering calculations, and didn't feel constrained to "round" it to the best option of 2 (generally) as is done in US (other?) designs. He also stated that because of the range of metric thread pitches (un)"common" across industries/countries/regions of origin, they simply didn't have the space to stock supplies to cover metric buyers. By stocking the leading pitches they cover many, but as he said, had to turn away many as well (almost never for "common" though having less stock volume!). They could get it shipped in (don't recall lead), but suggested I go by Kubota down the road since I wanted to finish my project. But then it turned out Kubota didn't even stock some of the bastard bolts used to fasten the "frame" plates to the block. They were going to be stupid cost AND waiting for delivery, if the mechanic hadn't taken pity and helped me go through his stash to find what I needed.

That said, I'm sure living in a nominally metric country would provide a higher hit rate, but again, that doesn't speak to the superiority of the metric fastener system. As far as I think I understand, if I had a home shop there, and wanted the same "on hand" coverage I currently enjoy with my "standard" fastener bins, I would need at least 3 times the space just to cover the same basic range. They have more nominal diameters, AND more thread pitches for each, multiplied by a few grades, hex/socket/button/etc. No thanks.

I don't think anyone would dream to argue against metric conversion convenience superiority. And there are other solid arguments for accepting the metric system. But the fastener story is vastly inferior, unless you are an anal engineer that wants to specify the exact perfect fastener for their oh so important tractor bracket...
Russ
Master Floor Sweeper

Post Reply